My 'Arizona bike' - the one I keep in AZ to ride when I visit - came to me with 22mm front and a (flat) 25mm rear. I had a problem with the little riding that I did out there last visit because the pavement is rough. The asphalt binder just 'goes away' in the desert summer heat, leaving an exposed aggregate pebble surface - at least on US60 from Apache Junction to Florence Juntion (AZ 79). That high pressure 22mm front tire beat the crap out of me. I had changed out the rear 25 for a heavy Vittoria Randonneur II 28mm, but am reconsidering. I'm going back out to AZ this next week, and bring two sets of new tires -- Vittoria Rubino Pro Tech III in both 25 and 28mm widths. We shall see...